Mo-containing low-carbon austenitic stainless steel has been used frequently as a component material for pipes and in-furnace structures of nuclear reactors because it is difficult to sensitize and has higher stress corrosion crack resistance under high-temperature and pressure water than an austenitic stainless steel containing no Mo.
However, in recent years, it has been revealed that in Mo-containing low-carbon austenitic stainless steel, stress corrosion cracks develop from regions which have been hardened by grinding or welding heat distortion. These cracks can propagate as intergranular stress corrosion cracking even if the stainless steel is not sensitized. Such a phenomenon is a new phenomenon that has not been studied conventionally. To take measures against this phenomenon, the development of a stainless steel having high stress corrosion crack resistance has become a pressing concern.